Pneumatic separators in sheet feeding devices



July 24, 1956 A. STOLZ 2,756,09

PNEUMATIC SEPARATORS IN SHEET FEEDING DEVICES 2 Sheets-Sheet l Filed July 27 1951 July 24, mm A. STOLZ 2,756,049

PNEUMATIC SEPARATORS IN SHEET FEEDING DEVICES Filed July 27, 1951 2 Sheets-Sheet 2 PM??? WM 6%;

United States Patent PNEUMATIC SEPARATORS IN SHEET FEEDING DEVICES Arnhold Stolz, Dusseldorf, Germany Application July 27, 1951, Serial N 0. 238,879

Claims priority, application Germany July 29, 1950 9 Claims. (Cl. 271-12) The invention relates to a sheet feeding apparatus having a plurality of reciprocally operating systems of suction devices, each of which systems detaches a sheet from the pile from time to time independently of the other and conveys it to the laying-on table, and has for its object the provision of a sheet feeding apparatus Which gives a greater Working speed Without increasing the speed of movement of the suction device and Without turning the sheets.

In known sheet feeding apparatus of the type referred to above, three or more suction devices are arranged on an arm system at an equal distance from each other and from the axis of the arm system. The arm system rotates about its axis in one direction, while each of the suction devices rotates about its axis in the other direction. The sheet feeding apparatus is arranged at the edge of the pile turned away from the laying-on table, above said pile. The suction devices, which are disposed in cylinders, remove a sheet from the pile in succession, the seized surface of the sheet being applied round the cylinder carrying the suction device, so that, owing to the rotation of the cylinder, the lower surface of the sheet becomes the upper surface. The sheet, having been thus turned, the suction cylinder, co-operating with a cylinder arranged at the front edge of the laying-on table of the machine, delivers it to the laying-on table. This known sheet feeding apparatus necessitates the turning of the sheets when they are fed to the laying-on table. In addition, it merely peels off the sheets from the pile, without being able to carry out the delivery movement to the laying-on table only after prior separation of the sheet from the pile. Also, it is not possible to deliver the sheets to the laying-on table in such a way that the sheets form a continuous staggered pile, in which the preceding sheet overlaps the following sheet.

According to the invention, oscillating suction systems having a reciprocal movement are employed in the sheet feeding apparatus of the type mentioned at the beginning. By this means, it is possible, on the one hand, even without increasing the speed of movement of the suction devices, to attain the greater working speed without any turning of the sheets and, on the other hand, in addition to the oscillating movement, the suction devices are also able to carry out an additional movement which is such that they are first lowered on to the pile and effect the separation of the uppermost sheet by a tilting movement,

are lifted again and they convey the sheet to the feeding so controlled that, while one suction system lifts a sheet from the pile, the other suction system can already apply suction to the sheet lying thereunder, in order to prevent the next sheet from sliding along as the uppermost sheet is carried away. In this connection, it is a matter of in- 7 difference whether single sheets are conveyed in succestable, in the manner which has been recognised as particusion on to the laying-on table or a continuous staggered pile is formed on the laying-on table.

The oscillating suction systems, which, in a manner known per se, in addition to the oscillating movement, carry out an additional movement which is such that they are first lowered on to the pile and effect the separation of the uppermost sheet from the pile by a tilting movement, are raised again and then convey the sheet to the laying-on table, can oscillate about one another, so that the suction devices avoid each other aloft.

It is advisable to associate a special feeler and control member for regulating the pile with each suction system. Likewise, each suction system can have a blowing device oscillating in unison.

According to the invention, in order to ensure the conveyance of the sheets on the laying-on table, which sheets reach the laying-on table in rapid succession, the laying-on table is not equipped with endless rotating belts, but with claws on endless rotating chains. The claws provide an absolute guarantee of the conveyance of the sheets on the laying-on table even when the suction systems are arranged at the rear edge of the piles of sheets and the sheets form a continuous staggered pile on the laying-on table.

Advantageously, the pivoting ends of the claws have an upwardly bent extension. By means of the extension, the entry of the end of the sheet into the claws is ensured. and the sheets are prevented from striking against the edge of the claw and from slipping over the claw or being sent too far.

The claws may have an irregular rotatory movement which is such that, when taking over a sheet, they almost remain at a standstill and then start off at greater speed. This offers the advantage that the gripping of the sheets by the claws is further improved and is of a more positive nature.

In machines with an oscillating arrangement, there is the possibility of conveying the sheet directly as far as the front marker of the processing machine by means of the rotating claws, While in machines without an oscillating arrangement, or in the event of pile formation of the sheets being lacking, additional roller bodies are provided co-axial with the chain wheel of the rotating claws on the side turned away from the pile, which roller bodies operate in conjunction with oscillating conveying rollers arranged above the laying-on table, in order to convey the sheet as far as the front marker.

It is advantageous to provide the claws mounted in such a way on the chains carrying them that, on opening, the claws move at accelerated speed in the direction of running. In this way, the claws do not hinder the progress of the sheet when the same is delivered. At the same time, a good grip on the sheets is ensured as they are received.

Each claw can have a spring mounting of its own, so that no truing and adjustment of the claws is necessary.

According to the invention, an electric motor driving the compressor can also operate the pile mechanism through a coupling.

The drawing illustrates diagrammatically two embodiments of the invention. a Figure 1 shows a longitudinal view of the sheet feeding apparatus with suction systems arranged at the rear edge of the pile;

Figure 2 illustrates a rear end elevational view of the device according to Figure 1;

Figure 3 reproduces a claw drawn in the closed position;

Figure 4 shows the opened claw;

Figure 5 shows the arrangement of the suction systems at the front edge of the pile operating under the paper track;

Figure 6 shows a drawing of the drive of the chains carrying the claws.

In the embodiment according to Figure 1, the two suction systems 1 and 2 are arranged to oscillate at the rear edge of the pile of paper above the latter. Both suction systems operate reciprocally. While, for example, the suction system 1 delivers a sheet B4 to the laying-on table 4, the suction system 2 detaches the next sheet B5 from the pile 3. In the embodiment, the transfer of the sheets to the laying-on table is carried out in such manner that the preceding sheet is still overlapping the following sheet, so that the sheets have a staggered arrangement on the laying-on table. Each suction system has associated therewith a blowing device 12 oscillating in unison, the suction and blowing being controlled by suitable valves of any, known. design.

The drive of the suction systems is effected through the bevellgeanwheel- 13 and the bevel pinions 13', the shafts of which carry two eccentric discs 14 and 15. The eccentric discs effect the tilting action and the raising action and also the pivoting movement of the suction systems for conveying the sheets to the laying-on table, as hereinafter described.

The laying-on table is equipped with claws 5 on endless rotating chains 6. Each claw has a spring mounting of its own, which, .in the embodiment illustrated, comprises a spring construction of the claw tongue 16. At their pivoting end, i. e. at the end of the claw tongue, the claws have an upwardly bent extension 7. Above the lower driving wheel of the chains carrying the claws, there are provided oscillating rollers 8 known per se, working in conjunction with further roller bodies, which latter are arranged to be co-axial with the lower supporting wheel 9 of the claw chains. In Figure 1 the sheet B2 has reached the oscillating rollers 8 and is being released by the claws. The sheet B1 is already lying straightened out at the front marker 10 of the processing machine. The claws located in the lower run of the chain are running open between the chain wheels 9 and 11 in an upward direction.

According to Figure 5, the suction systems 1 and 2 are arranged at the front edge of the pile 3. Here, the suction systems operate beneath the paper track, which the sheet Ba and the sheet B4 form. The drive of. the suc tion systems is carried out in accordance with Figure 2. The method of operation is as follows:

The suction system 1 separates the sheet B4 in manner known per so from the loosened pile, lifts it and advances it as far as the adjacent revolving claw 5. It transfers the sheet tothe claw while the claw executes a slow movement. The suction system 1, thusfree from the sheet, then swings forward beyond the front edge of the sheet and descends towards the front, so that the free sheet can be fed unobstructed to the processing machine. In the meantime, the suction system 2 ha separated the sheet B5 from the pile and swings it past the suction system 1 to the next following revolving claw 5. The suction system 1 has now once more arrived above the pile and separates the next sheet from the pile.

The mechanism for operating the suction systems is not fully shown and the feeler and control members are not separately indicated in the drawing, since the manner of arrangement thereof is already known. See for example Goodwin Patent No. 2,208,304, Sinkowitz Patent No. 2,372,299 and Schneider Patent No. 2,402,453, dated July 16, 1940, March 27, 1945 and June 18, 1946; respectively.

The irregular rotatory movement of the claws can, for example,.be achieved in the manner shown in Figure 6, in which the toothed wheels 18, 17 and 19 are provided for the drive. The toothed wheel 17 is equipped with a lateral rim, on which the lever 20 is mounted, which also serves for mounting the toothed wheel 18. The toothed wheel 18 is simultaneously mounted on the lever 21, which can pivot about the shaft of the toothed driving wheel 19 of the claw chain. The drive is carried out throughthe shaft 22, which drives the toothed wheel 17. Owing to the eccentricmounting of the toothed wheel 17 on the shaft 22, the toothed wheel 17 has an irregular circumferential speed,1i. e. the part of the periphery of the toothed wheel furthest removed from the shaft 22 has a greater circumferential speed than the part of the periphery of the toothed wheel lying nearer the shaft 22. The result of this is, that the toothed wheel 18, and hence also the toothed wheel 19, receive an irregular drive. The toothed wheel 18, in consequence of the mounting in the lever 20, can follow the movement caused by the eccentricity of the toothed wheel 17, the toothedwheel 18 and the lever 21 oscillating about the shaft of thetoothed wheel 19.

I claim:

1. Apparatus for separating sheets of paper from, a stack of sheets and feeding the sheets to a feed table, in which there are two groups each comprising a plurality of suction devices, and a single carrier member for each group, all the suction devices of each group being mounted on the associated carrier member and said carrier members being disposed transversely in relation to the feeding direction, one carrier member projecting over the stack laterally from one side of the stack of sheets and the other carrier member projecting over the stack laterally from the, opposite side of the stack of sheets, means causing each group of suction devices alternately to detach a sheet from the stack independently of the other group of suction devices and transport said sheet towards said feed table, said detaching and transporting means including separate pivotal supports each mounting one carrier member for swinging gyratory movements, and means controlling said movements of said carrier members whereby during such movements each carrier member alternately passes above the, other carrier member.

2. Sheet feeding apparatus as defined in claim 1, wherein the said two carrier members are maintained parallel with one another, and at the point in said movements when one carrier member is passing above the other carrier member, both carrier members he in the same plane at right angles to the direction of feed.

3. Sheet feeding apparatus as defined in claim 1, including drive means for moving said carrier members, ]said drive means being common for both of said memers.

4. Sheet feeding apparatus as defined in claim 1, comprisingmeans for swinging said suction systems alter nately. to and fro in the direction of feeding movements, means. for lowering each suction system alternately on to said. pile of sheets and for tilting said suction system in lowered position to detach a sheet from the pile and subsequently raising said suction system, and coordinating means. for guiding said suction systems around each other to feed a sheet and return to pick up another sheet.

5. Sheet feeding apparatus as defined in claim 1, comprising pivoted arms supporting said carriers for swing: ing said suction systems alternately to and fro in the direction of feeding movements to feed a sheet and return to pick up another sheet, pivoted members carried by said arms for lowering each suction system alternately on to said pile of sheets and for tilting said suction system in lowered position to detach a sheet from the pile and subsequently raising said suction system, and means cooperating with said such systems alternately to deliver a sheet and returnto pick up another sheet.

6. Apparatus for separating sheets of paper from a stack of sheets and feeding the sheets to a feed table, in which there are two groups of suction devices and a single carrier member for each group, all the suction devices "w my?" of each group being mounted on the associated carrier member, means supporting one carrier member with its suction devices to project over the stack from one side in relation to the feeding direction and means supporting the other carrier member with its suction devices to project over the stack from the opposite side, means for operating said groups of suction devices to cause each group of suction devices in alternation to detach a sheet from the stack independently of the other group of suction devices and transport said sheet towards said feed table, said means causing swinging gyratory movements of said carrier members and controlling said movements whereby each carrier member alternately passes directly above the other carrier member, separate blower means for each group of suction devices, and means for effecting swinging movements of each blower means in synchronism with the movements of its associated group of suction devices.

7. Sheet feeding apparatus as defined in claim 6, wherein the swinging movements of the blowers are maintained in parallel vertical planes on opposite sides of and adjacent to the midline of the apparatus.

8. Apparatus for separating sheets of paper from a stack of sheets and feeding the sheets to a sheet conveying means, said apparatus comprising two groups of suction devices each having at least two suction cups and each supported on a separate carrier, said carriers being pivoted on axes in transverse alinement disposed one on each side of the path of movement of said sheets, and projecting laterally towards each other above the stack from separate mounts located on opposite sides thereof, operating means for each group of suction devices, and conveying means for said sheets extending from said stack in the space between said mounts, said conveying means comprising sheet gripping means spaced along an endless carrier, variable speed driving means for said endless carrier having slow and fast periods of movement and operating in synchronism with said suction devices operating means to grip and move a sheet as delivered thereto alternately from each carrier, the gripping taking place during the slow movement of said endless carrier, and means for releasing said sheet gripping means at a predetermined position on said conveying means.

9. Sheet feeding apparatus as defined in claim 8, including a driving wheel for said endless carrier and means for rotating it at an irregular rate as compared with said suction device operating means, first roller means co-axial with said driving wheel and rotatable with respect thereto, second roller means parallel with said first roller means, and means for oscillating said second roller means, said first and second roller means cooperating with one another for removing said sheets from said sheet gripping means at a predetermined position lengthwise of said endless carrier.

References Cited in the file of this patent UNITED STATES PATENTS 

